From 60e73d24cfec506b966ff789c8420bc4f466f880 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Fri, 14 Dec 2012 14:08:12 +0100
Subject: Add a mechanism for embedding run-time functions into the generated
 code

---
 lib/asn1/src/asn1ct_func.erl | 105 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 lib/asn1/src/asn1ct_func.erl

(limited to 'lib/asn1/src/asn1ct_func.erl')

diff --git a/lib/asn1/src/asn1ct_func.erl b/lib/asn1/src/asn1ct_func.erl
new file mode 100644
index 0000000000..2d221ca1b9
--- /dev/null
+++ b/lib/asn1/src/asn1ct_func.erl
@@ -0,0 +1,105 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2012. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+%%
+
+-module(asn1ct_func).
+-export([start_link/0,need/1,call/3,generate/1]).
+-export([init/1,handle_call/3,handle_cast/2,terminate/2]).
+
+start_link() ->
+    {ok,Pid} = gen_server:start_link(?MODULE, [], []),
+    put(?MODULE, Pid),
+    ok.
+
+call(M, F, Args) ->
+    MFA = {M,F,length(Args)},
+    need(MFA),
+    asn1ct_gen:emit([F,"(",call_args(Args, ""),")"]).
+
+need(MFA) ->
+    asn1ct_rtt:assert_defined(MFA),
+    cast({need,MFA}).
+
+generate(Fd) ->
+    req({generate,Fd}),
+    erase(?MODULE),
+    ok.
+
+req(Req) ->
+    gen_server:call(get(?MODULE), Req, infinity).
+
+cast(Req) ->
+    gen_server:cast(get(?MODULE), Req).
+
+%%% Internal functions.
+
+-record(st, {used}).
+
+init([]) ->
+    St = #st{used=gb_sets:empty()},
+    {ok,St}.
+
+handle_cast({need,MFA}, #st{used=Used0}=St) ->
+    case gb_sets:is_member(MFA, Used0) of
+	false ->
+	    Used = pull_in_deps(gb_sets:singleton(MFA), Used0),
+	    {noreply,St#st{used=Used}};
+	true ->
+	    {noreply,St}
+    end.
+
+handle_call({generate,Fd}, _From, #st{used=Used}=St) ->
+    generate(Fd, Used),
+    {stop,normal,ok,St}.
+
+terminate(_, _) ->
+    ok.
+
+call_args([A|As], Sep) ->
+    [Sep,A|call_args(As, ", ")];
+call_args([], _) -> [].
+
+generate(Fd, Used0) ->
+    Used1 = gb_sets:to_list(Used0),
+    Used = sofs:set(Used1, [mfa]),
+    Code = sofs:relation(asn1ct_rtt:code(), [{mfa,code}]),
+    Funcs0 = sofs:image(Code, Used),
+    Funcs = sofs:to_external(Funcs0),
+    io:put_chars(Fd, Funcs).
+
+pull_in_deps(Ws0, Used0) ->
+    case gb_sets:is_empty(Ws0) of
+	true ->
+	    Used0;
+	false ->
+	    {MFA,Ws1} = gb_sets:take_smallest(Ws0),
+	    Used = gb_sets:add(MFA, Used0),
+	    Needs = asn1ct_rtt:dependencies(MFA),
+	    Ws = update_worklist(Needs, Used, Ws1),
+	    pull_in_deps(Ws, Used)
+    end.
+
+update_worklist([H|T], Used, Ws) ->
+    case gb_sets:is_member(H, Used) of
+	false ->
+	    update_worklist(T, Used, gb_sets:add(H, Ws));
+	true ->
+	    update_worklist(T, Used, Ws)
+    end;
+update_worklist([], _, Ws) -> Ws.
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